Stock material or miscellaneous articles – Structurally defined web or sheet – Discontinuous or differential coating – impregnation or bond
Reexamination Certificate
2000-04-11
2002-08-20
Hess, Bruce H. (Department: 1774)
Stock material or miscellaneous articles
Structurally defined web or sheet
Discontinuous or differential coating, impregnation or bond
C428S206000, C428S220000, C428S323000, C428S332000
Reexamination Certificate
active
06436515
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an ink jet recording sheet for producing high image quality, and specifically to an ink jet recording sheet which provides high quality ink jet prints which result in no imagewise gloss difference through minimization of glare due to the surface gloss.
BACKGROUND OF THE INVENTION
Accompanying the marked technical innovation of ink jet recording in recent years, ink jet print quality is approaching that obtained by conventional silver halide photography. Print quality obtained utilizing ink jet recording is dependent on printers, inks, and recording sheets. In terms of image quality, recent technical innovations of the former two play a major role, and the performance of the ink jet recording sheet (hereinafter occasionally referred to as a recording sheet) is now very important because it plays a critical role to differentiate final print quality.
In order to obtain prints close to silver halide photographic prints employing ink jet recording, various improvements have been carried out for recording sheets.
Ink jet recording sheets are mainly divided into the following two groups, one is comprised of a support such as paper which is inherently ink absorptive, and the other comprises a support having thereon an ink absorption layer. However, the former is difficult to produce high quality prints because high maximum density is not obtained due to the direct penetration of the ink into the support, and the support itself absorbs the ink solvent, resulting in formation of marked imagewise wrinkling, and the latter is preferable.
Known as two major types of ink absorption layers, provided on a support, are a swelling type ink absorption layer and a void type ink absorption layer.
The swelling type ink absorption layer is comprised of hydrophilic polymers such as gelatin, polyvinyl alcohol, polyvinylpyrrolidone, polyethyleneoxide and the like, as the main component.
The void type ink absorption layer which comprises void in a layer is prepared employing several types of production methods. The representative layer is comprised of a small amount of hydrophilic polymers and a large amount of fine particles. Voids are formed between said fine particles, into which ink is absorbed.
Texture occasionally is a personal preference. However, depending on the purpose of the print, glossiness, which is necessary to obtain high quality prints, and other properties, are occasionally required.
For instance, there are such demands that fingerprints do not show; staining due to adhesive materials such as paste occurs minimally, excessive reflection of light, which hinders viewing, is decreased, and the like.
The semi-matte surface is generally obtained by forming a surface unevenness in the order of 1 &mgr;m, for example. When ink jet recording is carried out employing a recording sheet of which surface is appropriately roughened, problems occur in which the glossiness varies in accordance with the image and tends not to be uniform. This problem particularly deteriorates the print quality, and thus, it is necessary to overcome it.
The cause of such uneven glossiness is not yet fully understood. However, it is assumed that when ink jet recording is carried out, low volatile organic solvents remain in the ink absorption layer and thus the fine roughness in the image area on the surface is different from that of the non-image area.
When such an imagewise non-uniform gloss difference is formed, glare results on the image surface. Consequently, the resulting prints do not look natural and are not accepted as high quality prints.
When a support does not absorb ink solvents, this problem becomes more pronounced. However, even when the support absorbs an ink, slight differences in roughness on the surface are formed via said ink jet recording and imagewise gloss difference results.
SUMMARY OF THE INVENTION
In view of the foregoing, the present invention was achieved. An object of the present invention is to provide an ink jet recording sheet which does not result in distinct imagewise gloss differences between the printed area and the non-printed area, minimizes glare due to surface gloss, and further is capable of forming high quality images without uneven image.
The aforementioned object of the present invention is achieved by the embodiments described below.
1. In an ink jet recording sheet which is subjected to surface treatment so as to form a fine grained surface having irregular or regular textured roughness on the surface on the ink absorption layer surface side of a support, an ink jet recording sheet characterized in having a center line average roughness (Ra) of 0.8 to 4.0 &mgr;m, measured at a standard length of 2.5 and a cut-off value of 0.8 mm of the surface on the ink absorption layer side, which is specified in JISB-0601 and a 60-degree specular gloss of 10 to 30 percent, specified in JIS-Z8741.
2. An ink jet recording sheet characterized in having a center line average roughness (Ra) of the surface on the ink absorption layer side of 0.8 to 4.0 &mgr;m measured at a standard length of 2.5 mm and a cut-off value of 0.8 mm, specified in JISB-0601, and a 60-degree specular gloss of 10 to 30 percent, specified in JIS-Z8741, while comprising said ink absorption layer on a support which is subjected to surface treatment so as to form a fine grained surface having irregular or regular textured roughness.
3. An ink jet recording sheet described in 1. or 2. above, characterized in having a center line average roughness (Ra) of a support of 1.0 to 5.0 &mgr;n, measured at a standard length of 2.5 mm and a cut-off value of 0.8 mm, specified in JISB-0601.
4. An ink jet recoding sheet described in 1., 2., or 3. above, characterized in that a support is comprised of paper laminated by a polyolefin resin on the both sides.
5
. An ink jet recording sheet described in claim
1
,
2
,
3
, or
4
, above, characterized in that an ink absorption layer is a porous film having voids therein.
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in further detail below.
The ink jet recording sheet of the present invention comprises an ink absorption layer on a support.
Employed as the support used in the present invention may be a water absorption support as well as a water non-absorption support. However, a water non-absorption support is preferably employed because it does not result in wrinkling and a semi-matte surface is readily obtained.
In case that the ink jet recording sheet has a water absorption support, it sometimes results in wrinkling because the support absorbs ink solvent and in lowering the image density because dyes adsorbed in the ink layer insinuate into the support during storage of the inked sheet.
In case that the ink jet recording sheet has a water non-absorption support, ink jet print having high quality appearance is obtained without such problems mentioned above.
As for the water absorption support, a paper support comprised of natural pulp as the main component is representative. However, said support may be comprised of a mixture of natural pulp and synthetic pulp.
Listed as water non-absorption supports are plastic resin films, and also supports comprised of paper which are laminated with a plastic resin film on both sides.
Listed as plastic resin film supports are polyester film, polyvinyl chloride film, polypropylene film, cellulose triacetate film, polystyrene film, and the like.
Either transparent or translucent plastic resin films may be employed. However, those, which are transparent, are preferred.
Preferred supports in the present invention are those comprised of paper, which are laminated with a plastic resin on both sides, and the most preferred supports are those in which both sides of paper are laminated with a polyolefin resin.
Specifically, recording sheets, which are comprised of a paper support laminated with polyolefin resins such as polyethylene and the like on both sides, having thereon an ink absorption layer, are preferable, because their cost is relatively low compared to plastic fi
Ohbayashi Keiji
Saito Yoichi
Yoshitsuka Kenichi
Bierman, Muserlian and Lucas
Hess Bruce H.
Konica Corporation
Shewareged B.
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